This invention relates to marine propulsion, and particularly to a novel helical screw ducted turbine.
Marine propulsion is usually achieved by accelerating water and propelling it away from the watercraft. Rapid acceleration of the water produces cavitation, which renders the efficiency of conventional propellers quite low.
It is an object of the present invention to provide a marine propulsion unit which avoids or minimizes the problem of cavitation by combining gradual acceleration with the use of ducting and secondary water inlets to cavitation-prone areas.